Enhancement of boiling heat transfer of thin water film on an electrified solid surface
Enhancement of boiling heat transfer of thin water film on an electrified solid surface
复制标题
带电固体表面薄水膜沸腾传热的增强
DOI：
10.1016/j.ijheatmasstransfer.2017.02.029
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发表时间：
2017-06-01
影响因子：
5.2
通讯作者：
Yan, Wei-Mon
中科院分区：
文献类型：
--
作者：
Wang, Bing-Bing;Wang, Xiao-Dong;Yan, Wei-Mon
当固体表面的温度或热通量超过临界值时，液体膜会发生快速沸腾，在液体膜和固体表面之间迅速形成蒸汽层，导致液体膜从固体表面脱离，从而显著降低传热速率。本文提出了一种新的观点，即固体表面带表面电荷，以抑制汽相层的形成和防止液膜的脱离。为了验证这一观点的有效性，我们采用分子动力学模拟方法研究了不同润湿性条件下金（100）表面水膜的沸腾行为，以及表面电荷的存在与否.结果表明，表面电荷产生的电场增强了水膜与金表面的吸引作用。同时，由于水分子沿电场方向沿着定向排列，形成了一个锥形液柱从水膜自由表面向上运动，有助于成核气泡突破水膜。因此，在水膜的整个相变过程中，蒸汽层的形成被抑制，并且从未观察到水膜脱离。结果还表明，电场显着增加了水分子和金原子之间的碰撞速率，从而增强了从金表面到水膜的热传递。(C)2017爱思唯尔有限公司版权所有
Rapid boiling of liquid film appears on solid surfaces with ultrahigh temperatures or heat fluxes, where a vapor layer is rapidly formed between the liquid film and the surface, leading to the film detachment from the surface and hence significantly reducing the heat transfer rate. In this work, a new idea, solid surface is charged with surface charges, is proposed to suppress the formation of vapor layer and prevent the liquid film detachment. To examine the effectiveness of the idea, the boiling behaviors of water films on gold (100) surfaces with various wettability conditions as well as with or without surface charges are investigated by molecular dynamics simulations. The results show that the electric field induced by the surface charges leads to an increased attractive interaction between the water film and the gold surface. Meanwhile, it is very interesting that a cone-shaped liquid column moves upward from the free surface of the water film due to the directional arrangement of water molecules along the electric field direction, which helps the nucleation bubble to break through the water film. Thus, the formation of vapor layer is suppressed and the water film detachment is never observed during the whole phase-change process of water film. The results also reveal that the electric field significantly increases the collision rate between water molecules and gold atoms, and hence enhances heat transfer from the gold surface to the water film. (C) 2017 Elsevier Ltd. All rights reserved.